Self-diffusion of rod-like viruses in the nematic phase

• DOI: 10.1209/epl/i2005-10127-x
• Publication Date: 2005-07-21T12:40:54Z
• Authors: M. P Lettinga; E Barry; Z Dogic
• Keywords: 0103 physical sciences; Soft Condensed Matter (cond-mat.soft); FOS: Physical sciences; 02 engineering and technology; Condensed Matter - Soft Condensed Matter; info:eu-repo/classification/ddc/530; 0210 nano-technology; 01 natural sciences; J; 3. Good health

We measure the self-diffusion of colloidal rod-like virus {\it fd} in an isotropic and nematic phase. A low volume fraction of viruses are labelled with a fluorescent dye and dissolved in a background of unlabelled rods. The trajectories of individual rods are visualized using fluorescence microscopy from which the diffusion constant is extracted. The diffusion parallel ($D_{\parallel}$) and perpendicular ($D_{\perp}$) to the nematic director is measured. The ratio ($D_{\parallel}/D_{\perp}$) increases monotonically with increasing virus concentration. Crossing the isotropic-nematic phase boundary results in increase of $D_{\parallel}$ and decrease of $D_{\perp}$ when compared to the diffusion in the isotropic phase ($D_{iso}$).<br/>7 pages, 4 figures, to appear in Europhysics Letters<br/>